1. Field of the Invention
Embodiments of the present invention are generally related to fluid circulation arrangements in a dishwashing appliance and, more particularly, to fluid circulation arrangements and methods for providing a concentrated and/or intensified wash effect in a dishwasher.
2. Description of Related Art
A dishwasher typically includes a tub portion for receiving dishware to be washed, wherein the tub portion defines a front or forward opening having a door member pivotably engaged therewith for sealing the opening. Often, the tub portion defines an interior space substantially in the form of a cube or elongate cube. However, dishwashing fluid, such as water, is normally sprayed or otherwise distributed over the contents of the tub portion by centrally (and horizontally) disposed rotating spray arms. As such, the dishwashing fluid is generally distributed in a substantially cylindrical configuration within the tub portion to achieve broad coverage and impingement of the dishwashing fluid on the dishware therein.
However, in some testing regimens serving bowls that include/represent baked on food soils may receive low scores since, in many areas of the dishwasher rack (within the tub portion) the jet intensity and dishwashing fluid coverage from the spray arms may not be sufficient to break up and remove heavy or baked-on food soils. In this regard, there may be generally three impediments to effective removal of heavy or baked-on soils: 1) there are baked-on or heavy food soils that are very difficult, in any event, to remove using conventional spray jets from the spray arms during a typical or extended dish washing cycle. To be able to remove these soils, an increase in pressure, time, coverage, and/or temperature may be beneficial. However, combinations of these parameters spread throughout the entire dishwasher and wash cycle may require a disproportional amount of energy to be consumed to clean the few dishware items with baked-on or heavy soils, versus the remainder of the dishware items wherein the majority of the soils may typically range from light to moderate in magnitude and/or cleaning difficulty; 2) a typical dishwasher spray arm may be designed to cover and clean all types of dishware that is dispersed within the dishwasher rack(s). To maximize the spray jet impingement on the soiled surface of such dishware, the dishware may be placed in the rack(s) in a horizontal orientation to maximize exposure to the dishwashing fluid dispensed from the typical horizontally-disposed rotating spray arm configuration. Such dishware, which may be large in usable surface area, would severely limit the amount of dishware items that could be loaded in the rack, if such items are placed in a horizontal orientation; and 3) due to the nature of baked-on or heavy soils, such soiled dishware may require specialized provisions for more concentrated and intensified exposure to the dishwashing fluid to enable such soils to be removed therefrom.
As such, there exists a need for an apparatus and associated method for concentrating and/or intensifying the distribution of dishwashing fluid in a dishwasher, whether selectively or on-demand, to achieve “focused” cleaning power on a particular area within the tub portion, in addition to or in the alternative to conventional spray arm technology, and possibly in the alternative to some “zone cleaning” schemes.